This invention relates generally to handles for power tools and more particularly to ergonomically adjustable tool dead handles which provide for operator comfort and convenience in a wide range of operating positions.
Use of handheld power tools may require holding the tools in a variety of positions in order to cut, rind, drill, fasten, or perform other operations on a workpiece. Depending on the size or nature of the tool, prolonged out of position operation may lead to serious discomfort and fatigue for the operator. In addition, the nature of some operations involves a possibility of tool jamming, kickback, or other irregularities which may unexpectedly transmit shock loads to the operator's arms.
Usually, if appropriate, power tools are equipped with auxiliary dead handles in addition to the operating trigger grip handle. Some dead handles are permanently fixed to the tool body and cannot be moved. Some other handles, however, may be attached at two or more locations on the tool body in order to optimize the operator's hand locations. Generally, the handles are provided as cylinders, tapered cylinders, or bulbous knobs, and, by permitting the use of two hands in manipulating the tool, improve efficiency by reducing operator fatigue and discomfort.
The dead handles described above are fixed in their angular relationship with the tool body. This, coupled with the circular cross section of the handles which tend to transmit more concentrated physical shock and vibration to the operator's hands and fingers, often forces the operator to maintain his hands and arms in an uncomfortable position which can cause excessive fatigue and a rapid deterioration of accuracy and efficiency.
Other tool handles have been provided which are adjustable incrementally around the axis of the handle. A typical adjustable handle assembly is shown in FIGS. 1 and 2 and, as described in detail below, incorporates a grip handle 11 which may be adjusted in incremental positions. This conventional handle assembly, however, suffers from the inherent drawback that only a finite limit of handle positions may be achieved. Moreover, such conventional adjustable handles are typically attached to a tool body by bottoming out an anchor bolt 24 into a tool body and rely solely on the torque of the anchor bolt to retain the handle in place. As a result, these conventional handles suffer from the drawback that they are easily loosened by tool vibration during operation.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.